Comment by lmeyerov

This is neat, I like the direction!

As far as I can tell, it's runtime, not static, so it won't help during our mypy static checks period?

As intuited by the poster above, we already do generally stick to Apache Arrow column types for data we want to control. Anything we do there is already checked dynamically, such as at file loads and network IO (essentially contracts), and Arrow IO conversions generally already do checks at those points. I guess this is a lightweight way to add stronger dynamically-checked contracts at intermediate function points?